It used to be a San Francisco treat. But now, sleek European-style streetcars also rumble through Portland, taking travelers on an invigorating five-mile loop. The air-conditioned cars roll through old Nob Hill neighborhoods, across the campus of Portland State University, and through the Pearl District, an area known for its top-notch art galleries and restaurants. (877) 678-5263, www.portlandstreetcar.org —